WO2024014564A1 - Display device comprising composite filler - Google Patents

Abstract

The present invention is applicable to the technical field of display devices and relates to a display device using, for example, a light emitting diode (LED). To this end, the present invention may comprise: a wiring board; an electrode pad partitioned on the wiring board; a plurality of light emitting diodes connected to the electrode pad to form unit pixels; an encapsulation layer formed on the wiring board to cover the plurality of light emitting diodes; an optical film positioned on the encapsulation layer; and a light scattering agent dispersed and distributed within the encapsulation layer, wherein the light scattering agent may comprise: a first light scattering agent; and a second light scattering agent having a scattering degree different from that of the first light scattering agent.

Description

Display device comprising composite filler

The present invention is applicable to display device-related technical fields, for example, relates to a display device using LED (Light Emitting Diode).

As the information society develops, the demand for display devices in various forms is increasing, and in response to this, in recent years, LCD (Liquid Crystal Display Device), PDP (Plasma Display Panel), ELD (Electro luminescent display), and VFD (Vacuum Fluorescent) have been developed. Various display devices such as display, OLED (Organic Light Emitting Diode), and micro LED (Micro Light Emitting Diode) are being researched and used.

Digital Signage is a communication tool that can induce marketing, advertising, training effects, and customer experience for companies, as well as general TV, in public places such as airports, hotels, hospitals, and subway stations. It is a display device that provides not only broadcast programs but also specific information.

Digital signage uses LCD (Liquid Crystal Display), PDP (Plasma Display Panel), OLED (Organic Light Emitting Diode), Micro LED (Light Emitting Diode), etc. on devices such as outdoor locations or street furniture. It is a medium that displays various contents and commercial advertisements by installing display panels. It can be installed not only in homes but also in the public movement lines such as apartment elevators, subway stations, subways, buses, universities, banks, convenience stores, discount stores, and shopping malls. there is.

Recently, as digital signage has become larger and larger, much research has been conducted to improve the image quality of display panels.

Such digital signage is implemented as a modular display device composed of several display modules combined. These module displays can use light emitting elements (LEDs) as pixels.

However, after constructing a pixel with an LED, the color of each module may appear different depending on the viewing angle due to the structural tilt of the LED and the difference in beam angle between chips.

Therefore, a solution to these problems is emerging.

According to an embodiment of the present invention, an object of the present invention is to provide a display device including a composite filler that can improve the refractive index by increasing light scattering of the display device.

In addition, an object is to provide a display device including a composite filler (light scattering agent) that can exhibit a large scattering effect even when a small amount is added.

In addition, it is intended to provide a display device including a composite filler in which the refractive index can be changed through changes in combination with various types of scattering agents and the overall content of scattering agents can be reduced.

As a first aspect of the present invention for achieving the above-described object, there is provided a wiring board; electrode pads defined on the wiring board; a plurality of light emitting elements connected to the electrode pads to form unit pixels; an encapsulation layer formed on the wiring board to cover the plurality of light emitting devices; An optical film positioned on the encapsulation layer; and a light scattering agent dispersed and distributed within the encapsulation layer, wherein the light scattering agent includes: a first light scattering agent; And it may include a second light scattering agent having a different scattering degree from the first light scattering agent.

As an exemplary embodiment, the light scattering agent may include at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof.

As an exemplary embodiment, the encapsulation layer includes: a first layer covering the plurality of light emitting devices; And it may include a second layer located on the first layer.

As an exemplary embodiment, the second light scattering agent may be included in the second layer.

As an exemplary embodiment, the scattering degree of the first light scattering agent may be greater than the scattering degree of the second light scattering agent.

As an exemplary embodiment, the encapsulation layer may further include a third layer located on the side of the plurality of light emitting devices.

As an exemplary embodiment, the third layer may include a third light scattering agent having a different scattering degree from the first light scattering agent and the second light scattering agent.

As an exemplary embodiment, the scattering degree of the third light scattering agent may be higher than the scattering degree of the first light scattering agent and the second light scattering agent.

As an exemplary embodiment, the height of the third layer may be equal to or smaller than the height of the light emitting device.

As an exemplary embodiment, it may further include a side optical layer located on a side of the encapsulation layer.

As an exemplary embodiment, the side optical layer may include a fourth light scattering agent having a different scattering degree from the first light scattering agent and the second light scattering agent.

As an exemplary embodiment, the diameter or size of the light scattering agent may be 10 nm to 10 μm.

As a second aspect of the present invention for achieving the above-described object, the present invention includes a wiring board; electrode pads defined on the wiring board; a plurality of light emitting elements connected to the electrode pads to form unit pixels; an encapsulation layer formed on the wiring board to cover the plurality of light emitting devices; An optical film positioned on the encapsulation layer; and a filler dispersed and distributed within the encapsulation layer, wherein the filler includes: a first filler containing Zr oxide; and a second filler containing Si oxide.

As an exemplary embodiment, the encapsulation layer includes: a first layer covering the plurality of light emitting devices; And it may include a second layer located on the first layer.

As an exemplary embodiment, the second filler may be included in the second layer.

As an exemplary embodiment, the encapsulation layer may further include a third layer located on the side of the plurality of light emitting devices.

As an exemplary embodiment, the third layer may include a third filler having different optical properties from the first filler and the second filler.

As an exemplary embodiment, the third filler may include Ti oxide.

As an exemplary embodiment, the degree of light scattering of the third filler may be higher than that of the first filler and the second filler.

As an exemplary embodiment, it further includes a side optical layer located on a side of the encapsulation layer, and the side optical layer includes a fourth scattering agent having a different scattering degree from the first light scattering agent and the second light scattering agent. You can.

According to an exemplary embodiment of the present invention, the following effects are achieved.

First, the light scattering agent is a material with a relatively high refractive index and has the effect of improving the refractive index. A light scattering agent having such a large refractive index can exert a large scattering effect even when added in a small amount.

For example, a light scattering agent having a small size may have stability against the dispensing process. In addition, it can have the advantage of less sedimentation after going through the curing process after the dispensing process.

In addition, when two or more types of light scattering agents are mixed and used in the same layer, both types of light scattering agents may exert a light scattering effect, or one light scattering agent may be used to prevent sedimentation of the other main light scattering agent. You can.

In addition, when two or more light scattering agents are used together, the refractive index can be changed through a change depending on the combination of several types of scattering agents, and the overall content of the scattering agent can be reduced.

1 is a cross-sectional schematic diagram showing a display device according to a first embodiment of the present invention.

Figure 2 is a cross-sectional schematic diagram showing a display device according to a second embodiment of the present invention.

Figure 3 is a graph showing the characteristics of a light scattering agent used in a display device according to an embodiment of the present invention.

Figure 4 is a comparative example, a graph showing the change in luminance according to the viewing angle of the display device in a state in which a light scattering agent is not applied.

Figure 5 is a graph showing the change in luminance for each viewing angle of a display device according to an embodiment of the present invention.

Figure 6 is a cross-sectional schematic diagram showing a display device according to a third embodiment of the present invention.

Figure 7 is a cross-sectional schematic diagram showing a display device according to a fourth embodiment of the present invention.

Figure 8 is an enlarged view of the side optical layer of the display device according to the fourth embodiment of the present invention.

Hereinafter, embodiments disclosed in the present specification will be described in detail with reference to the attached drawings. However, identical or similar components will be assigned the same reference numbers regardless of reference numerals, and duplicate descriptions thereof will be omitted. The suffixes “module” and “part” for components used in the following description are given or used interchangeably only for the ease of preparing the specification, and do not have distinct meanings or roles in themselves. In addition, in describing the embodiments disclosed in this specification, to the extent that it is judged that a detailed description of related known technologies may obscure the gist of the embodiments disclosed in this specification, the embodiments disclosed in this specification will be described in detail with reference to the attached drawings. In the description, identical or similar components will be assigned the same reference numbers regardless of reference numerals, and duplicate descriptions thereof will be omitted. The suffixes “module” and “part” for components used in the following description are given or used interchangeably only for the ease of preparing the specification, and do not have distinct meanings or roles in themselves. Additionally, in describing the embodiments disclosed in this specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in this specification, the detailed descriptions will be omitted. In addition, it should be noted that the attached drawings are only for easy understanding of the embodiments disclosed in this specification, and should not be construed as limiting the technical idea disclosed in this specification by the attached drawings.

Furthermore, although each drawing is described for convenience of explanation, it is within the scope of the present invention for a person skilled in the art to implement another embodiment by combining at least two or more drawings.

Additionally, when an element such as a layer, region or substrate is referred to as being “on” another component, it is to be understood that it may be present directly on the other element or that there may be intermediate elements in between. There will be.

The display device described in this specification is a concept that includes all display devices that display information using a unit pixel or a set of unit pixels. Therefore, it is not limited to finished products but can also be applied to parts. For example, a panel corresponding to a part of a digital TV also independently corresponds to a display device in this specification. Finished products include mobile phones, smart phones, laptop computers, digital broadcasting terminals, PDAs (personal digital assistants), PMPs (portable multimedia players), navigation, Slate PCs, Tablet PCs, and Ultra This may include books, digital TVs, desktop computers, etc.

However, those skilled in the art will easily understand that the configuration according to the embodiments described in this specification may be applied to a device capable of displaying, even if it is a new product type that is developed in the future.

In addition, the semiconductor light emitting device mentioned in this specification includes LED, mini LED, micro LED, etc., and may be used interchangeably.

1 is a cross-sectional schematic diagram showing a display device according to a first embodiment of the present invention.

As shown in FIG. 1, the display panel 200 can implement an image by unit pixels 210 (211, 212, 213) arranged on the substrate 230. An encapsulation layer 240 may be formed on these unit pixels 210 (211, 212, 213).

Unit pixels 210 (211, 212, 213) may be formed by light emitting elements (211, 212, 213). For example, the unit pixel 210 may include a red light-emitting device 211, a green light-emitting device 212, and a blue light-emitting device 213.

The red light-emitting device 211, green light-emitting device 212, and blue light-emitting device 213 forming the unit pixel 210 may be electrically connected to the electrode pad 220 arranged on the substrate 230.

Meanwhile, unlike shown, the unit pixel 210 may include a stacked light emitting device (LED) with red, green, and blue colors in a single chip structure.

A composite optical film 100 may be positioned on the display panel 200. In this way, the composite optical film 100 can be attached to the display panel 200. The display panel 200 to which the composite optical film 100 is attached may be referred to as a display device 10.

Although not shown separately, a modular display device that implements a larger display area can be implemented by combining a plurality of display devices 10. For example, the display device 10 may be one display module that forms a modular display device. In this way, a plurality of display devices 10 can be combined in parallel to form a modular display device. A detailed description of this will be omitted.

Here, the optical film 100 may include a black dye layer 101 attached to the display panel 200. Although not separately shown, the optical film 100 may include a matrix. This matrix may include an adhesive layer and a transparent protective layer. Additionally, a separate optical film may be further provided.

The encapsulation layer 240 may be disposed on the substrate 230 provided with the electrode pad 220. The encapsulation layer 240 is made of an insulating and flexible material such as polyimide (PI), PET, or PEN, and can be integrated with the substrate 230 to form one substrate. In this way, the substrate 230 provided with the electrode pad 220 may be a wiring substrate with a wiring electrode (not shown) connected to the electrode pad 220. Hereinafter, an example in which the substrate 230 is a wiring board 230 will be described, and the substrate and the wiring board will be described using the same reference numerals.

The encapsulation layer 240 may include fillers 250 and 251. These fillers 250 and 251 may include a first filler 250 and a second filler 251 having different optical properties.

Here, the optical characteristic may be a characteristic of refracting or scattering light emitted from the light emitting device 210.

Light emitted from the light emitting elements 211, 212, and 213 may be refracted or scattered by the pillars 250 and 251. Light scattered from the fillers 250 and 251 may be emitted to the outside of the encapsulation layer 240.

After cured, the encapsulation layer 240 may be transparent. For example, the cured encapsulation layer 240 containing silicon may have a refractive index of 1.4 to 1.6. Accordingly, light may be totally reflected inside the encapsulation layer 240. The fillers 250 and 251 may refract or scatter light that is totally reflected inside the encapsulation layer 240.

That is, the fillers 250 and 251 may act as light scattering agents. Therefore, the fillers 250 and 251 may be referred to as light scattering agents. In the following description, the filler and the light scattering agent may refer to the same entity.

The fillers 250 and 251 may include at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof. For example, the fillers 250 and 251 may be spherical or amorphous. For example, the first filler 250 may be amorphous and the second filler 251 may be spherical.

Additionally, the diameter or size of the fillers 250 and 251 may be 10 nanometers (nm) to 10 micrometers (㎛). The content (weight ratio) of these fillers 250 and 251 may be 0.01% to 30% of the encapsulation layer 240.

For example, the first filler 250 may include Zr oxide. Additionally, as an example, the second filler 251 may include Si oxide.

At this time, the optical characteristics of the first pillar 250 may be different from the optical characteristics of the second pillar 251. As mentioned above, the optical characteristic may be a characteristic of refracting or scattering light emitted from the light emitting device 210.

Additionally, the characteristic of refracting or scattering light emitted from the light emitting device 210 can be expressed as a scattering degree.

In this way, the encapsulation layer 240 may include light scattering agents 250 and 251, and the light scattering agents 250 and 251 include the first light scattering agent 250 and the first light scattering agent 250. and a second light scattering agent 251 having a different scattering degree.

This scattering degree can be confirmed by measuring the luminous intensity of the scattered light generated after irradiating the excitation light. At this time, blue light (for example, wavelength 435 nm or 450 nm) may be used as the excitation light.

Meanwhile, the degree of scattering can be defined as the degree to which light emitted from the light emitting devices 211, 212, and 213 is scattered relative to unit mass.

In this way, the color difference of light emitting devices can be improved by using a composite light scattering agent including the first filler (250; first light scattering agent) and the second filler (251; second light scattering agent) and surface haze. The (Haze) phenomenon can be improved.

The light scattering agents 250 and 251 may interfere with the straight path of light emitted from the light source (light-emitting device) forming the unit pixels 211, 212, and 213, causing light scattering, a type of random reflection. Therefore, the light scattering agents 250 and 251 can prevent the luminance deviation phenomenon in which the light emitted from the unit pixels 211, 212, and 213 is biased in a specific direction.

In addition, the light scattering agents 250 and 251 can improve the phenomenon in which colors appear differently depending on the left and right positions and angles relative to the position of the substrate 230 (for example, a phenomenon in which the decrease in luminance is not uniform). .

When using a composite light scattering agent containing a first filler (250; first light scattering agent) and a second filler (251; second light scattering agent), the scattering effect can be increased, and a high content of filler (light scattering agent) can be used. j) can be added.

For example, 10 to 20 wt% of Si oxide (SiO ₂ ) compared to the weight of the base material such as silicone used as an example of the encapsulation layer 240 is 0.5 to 1 weight of Zr oxide (ZrO ₂ ). It may have a scattering effect similar to %. Additionally, it may have a scattering effect similar to 0.001 to 0.005% of Ti oxide (TiO ₂ ).

In this way, based on the scattering degree, the order is TiO ₂ > ZrO ₂ > SiO ₂ , so using TiO ₂ may be most effective, but TiO ₂ may cause a white turbidity phenomenon. Additionally, if a very small amount of scattering agent is used in actual product application, problems may occur due to weight error. Therefore, as suggested in the embodiments of the present invention, a plurality of scattering agents can be mixed and used. This will be described in detail later.

As described above, unit pixels of the display panel 200 may be implemented by light-emitting devices. In an embodiment of the present invention, a light emitting diode (LED) is exemplified as a type of semiconductor light emitting device that converts current into light.

The substrate 230 may include glass or polyimide (PI). In order to implement a flexible display, the substrate 230 may be made of any insulating and flexible material, such as PEN (Polyethylene Naphthalate) or PET (Polyethylene Terephthalate). Additionally, the substrate 230 may be made of either a transparent or opaque material.

The substrate 230 may be a wiring board on which an electrode pad 220 and a wiring electrode (not separately shown) following the electrode pad 220 are disposed, so that the electrode pad 220 is placed on the substrate 230. can be located

The encapsulation layer 240 may be disposed on the substrate 230 where the electrode pad 220 is located. The encapsulation layer 240 is made of an insulating and flexible material such as polyimide (PI), PET, or PEN, and can be integrated with the substrate 230 to form one substrate.

Light-emitting elements forming each unit pixel 211, 212, and 213 may be connected to the electrode pad 220. Hereinafter, as an example, a unit subpixel may have the same meaning as a light emitting device. Therefore, description will be made using the same reference numerals. For example, three unit sub-pixels may form one pixel. That is, the red (R) light-emitting device 211, the green light-emitting device 212, and the blue light-emitting device 213 may form one pixel.

The semiconductor light emitting devices 211, 212, and 213 that form such unit pixels may be micro LEDs having a size of several to hundreds of microns. In some cases, the semiconductor light emitting devices 211, 212, and 213 may be mini LEDs that are dozens of times larger than micro LEDs. Here, the mini LED may be different from the micro LED in terms of size and stacking structure. Specifically, the mini LED may further include a growth substrate for growing a semiconductor layer.

As an example of a semiconductor light emitting device (211, 212, 213) forming a unit pixel, a micro LED or mini LED is a type in which red (R), green (G), and blue (B) LEDs emit independently, as well as a single LED. It may have a stacked LED form consisting of red (R), green (G), and blue (B) layers.

A thin film transistor (TFT) is connected to the wiring electrode 241 to implement an active matrix (AM) type display device. For example, the substrate 230 may be a TFT substrate. As another example, the substrate 230 may be a passive matrix (PM) type substrate.

In Figure 1, the structure of the display panel 200 is simplified and briefly shown. Hereinafter, a description of the specific configuration of the display panel 200 will be omitted.

As mentioned above, the composite optical film 100 may be positioned on the display panel 200.

The optical film 100 may include a black dye layer 101. The black dye layer 101 is a black dye having a preset transmittance, and can reduce the degree to which the transparent protective layer 101 is exposed to ultraviolet rays. For example, the black dye layer 101 may have a transmittance of 10% to 60%. At this time, the black dye layer 101 may include a UV blocker to increase the UV blocking effect. This black dye layer 101 can perform the function of increasing the contrast ratio.

Meanwhile, as described above, the light scattering agents 250 and 251 are materials with a relatively high refractive index and have the effect of improving the refractive index. Light scattering agents 250 and 251 having such a high refractive index can exert a large scattering effect even when added in a small amount.

In one example, the light scattering agents 250 and 251 may have an amorphous particle shape with a median size of approximately 20 nm to 1 μm. These light scattering agents 250, 251 can be added into the encapsulation layer 240 through a dispensing process. The light scattering agents 250, 251 having the above small size can be stable against the dispensing process. . In addition, it can have the advantage of less sedimentation after going through the curing process after the dispensing process.

As an exemplary embodiment, the light scattering agents 250 and 251 may include Zr oxide (eg, ZrO ₂ ). Since this Zr oxide is a material with a high refractive index (2.3), it can have a relatively large scattering effect.

As described above, Zr oxide has a greater refractive index than silicon oxide (SiO ₂ ), so it can exert a large scattering effect.

As in the first embodiment, when two or more types of light scattering agents (250, 251) are mixed and used in the same layer (encapsulation layer; 240), both types of light scattering agents (250, 251) have the effect of light scattering. or one light scattering agent (e.g., second scattering agent 251) may be used to prevent sedimentation of another major light scattering agent (e.g., first scattering agent 250). there is.

Based on the light scattering data (unit: uW/cm2/nm) of the light scattering agent with the highest light scattering degree constituting the encapsulation layer (240; resin layer), the light scattering degree in the case of the first light scattering agent 250 is It may be from 0 to less than 100, and the light scattering degree of the second light scattering agent 251 may be from 0 to less than 50.

In this way, when two or more types of light scattering agents 250 and 251 are used, a light scattering agent having a large specific surface area can be used to prevent the light scattering agents 250 and 251 from settling. At this time, when using a spherical light scattering agent with a small specific surface area, a light scattering agent with a particle size (based on D50) of 10 ㎛ or less can be used.

If the size of the light scattering agent is 10 ㎛ or more, a phenomenon in which a large number of light scattering agents settle may occur, and these settled light scattering agents may cover the upper side of the light emitting device 210, resulting in luminance unevenness at each pixel location. there is.

Here, the meaning of D50 (median value) is that in the case of a particle-type light scattering agent, the particle density distribution is important, so the median value is used rather than the average value. Since the size of all particles has a distribution, when sorting from small to large, D50 can mean the size of the particle in the middle. For example, if there are 100 particles, D50 may mean the size of the particle corresponding to the 50th order.

Meanwhile, in order to prevent the light scattering agents 250 and 251 from settling within the encapsulation layer 240 and not being evenly distributed within the encapsulation layer, surface treatment may be performed on the light scattering agents. For example, a polar ionic bond or -OH functional group can be coated on the surface of the light scattering agent. Additionally, as another example, a fluidity modifier may be added to the surface of the light scattering agent. In the case of fluidity modifier, less than 10% of the light scattering agent content may be added. This may be to prevent an increase in thixotropy due to the influence of the fluidity modifier.

Figure 2 is a cross-sectional schematic diagram showing a display device according to a second embodiment of the present invention.

As shown in FIG. 2, the display panel 200 can implement an image by unit pixels 210 (211, 212, 213) arranged on the substrate 230. Encapsulation layers 241 and 253 may be formed on these unit pixels 210 (211, 212, 213).

Unit pixels 210 (211, 212, 213) may be formed by light emitting elements (211, 212, 213). For example, the unit pixel 210 may include a red light-emitting device 211, a green light-emitting device 212, and a blue light-emitting device 213.

The red light-emitting device 211, green light-emitting device 212, and blue light-emitting device 213 forming the unit pixel 210 may be electrically connected to the electrode pad 220 arranged on the substrate 230.

Meanwhile, unlike shown, the unit pixel 210 may include a stacked light emitting device (LED) with red, green, and blue colors in a single chip structure.

A composite optical film 100 may be positioned on the display panel 200. In this way, the composite optical film 100 can be attached to the display panel 200. The display panel 200 to which the composite optical film 100 is attached may be referred to as a display device 10.

As an exemplary embodiment, the encapsulation layers 241 and 253 include a first layer 241 covering a plurality of light emitting devices 211, 212, and 213, and a second layer 253 located on the first layer 241. ) may include.

The encapsulation layers 241 and 253 may include fillers 250 and 252. These fillers 250 and 252 may include a first filler 250 and a second filler 252 having different optical properties. Here, the optical characteristic may be a characteristic of refracting or scattering light emitted from the light emitting device 210.

Light emitted from the light emitting elements 211, 212, and 213 may be refracted or scattered by the pillars 250 and 252. Light scattered from the fillers 250 and 252 may be emitted to the outside of the encapsulation layers 241 and 253.

After the encapsulation layers 241 and 253 are cured, they may be transparent. For example, the cured encapsulation layers 241 and 253 containing silicon may have a refractive index of 1.4 to 1.6. Accordingly, light may be totally reflected inside the encapsulation layers 241 and 253. The fillers 250 and 252 may refract or scatter light that is totally reflected inside the encapsulation layers 241 and 253.

That is, the fillers 250 and 252 may act as light scattering agents. Accordingly, the fillers 250 and 252 may be referred to as light scattering agents. In the following description, the filler and the light scattering agent may refer to the same entity.

Referring to FIG. 2, the first filler 250 (first light scattering agent) may be included in the first layer 241, and the second filler 252 (second light scattering agent) may be included in the second layer 253. may be included.

In this way, the first filler 250 and the second filler 252 may be included in different encapsulation layers 241 and 253.

As an exemplary embodiment, the scattering degree of the first light scattering agent 250 may be greater than the scattering degree of the second light scattering agent 252.

The fillers 250 and 252 may include at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof. For example, the fillers 250 and 252 may be spherical or amorphous. For example, the first filler 250 may be amorphous and the second filler 252 may be spherical.

As described above, for example, the first filler 250 may include Zr oxide. Additionally, as an example, the second filler 252 may include Si oxide.

At this time, the optical characteristics of the first pillar 250 may be different from the optical characteristics of the second pillar 252. As mentioned above, the optical characteristic may be a characteristic of refracting or scattering light emitted from the light emitting device 210.

Additionally, the characteristic of refracting or scattering light emitted from the light emitting device 210 can be expressed as a scattering degree. Redundant descriptions of scattering diagrams will be omitted.

As such, according to an embodiment of the present invention, the color of light emitting devices is improved by using a composite light scattering agent including a first filler (250) and a second filler (252). The car can be improved and the surface haze phenomenon can be improved.

The light scattering agents 250 and 252 may interfere with the straight path of light emitted from the light source (light-emitting device) forming the unit pixels 211, 212, and 213, causing light scattering, which is a type of random reflection. Therefore, the light scattering agents 250 and 252 can prevent the luminance deviation phenomenon in which the light emitted from the unit pixels 211, 212, and 213 is biased in a specific direction.

In addition, the light scattering agents 250 and 252 can improve the phenomenon in which colors appear differently depending on the left and right positions and angles relative to the position of the substrate 230 (for example, a phenomenon in which the decrease in luminance is not uniform). .

When using a composite light scattering agent containing a first filler (250; first light scattering agent) and a second filler (252; second light scattering agent), the scattering effect can be increased, and a high content of filler (light scattering agent) can be used. j) can be added.

For other parts not described, the description of the first embodiment described above may be applied in the same manner. Therefore, redundant explanations are omitted.

In the case of this second embodiment, the first light scattering agent 250 included in the first layer 241 may be used to increase the light scattering effect of the side portion of the light emitting device 210 chip. Therefore, in this case, the scattering degree of the first light scattering agent 250 may be higher than the scattering degree of the second light scattering agent 252.

In this way, the light scattering effect can be increased by using two light scattering agents 250 and 252 with different scattering degrees and particle sizes.

In the second embodiment, as the thickness of the encapsulation layer (resin layer) 241 increases, the encapsulation layer 241 may be divided into a plurality of layers and the light scattering agent may be included in order to reduce sedimentation of the light scattering agent due to gravity.

At this time, the resin constituting the first layer 241 may be a resin capable of IR rapid curing or UV curing to prevent sedimentation.

Figure 3 is a graph showing the characteristics of a light scattering agent used in a display device according to an embodiment of the present invention.

Referring to FIG. 3, Zr oxide (ZrO ₂ ) that can be used as the first filler (250; first light scattering agent) described above and Si that can be used as the second filler (251 or 252; second light scattering agent) It shows the scattering degree of oxide (SiO ₂ ).

As described above, the characteristic of refracting or scattering light emitted from the light emitting device 210 can be expressed as a scattering degree.

The scattering diagram shown in FIG. 3 may represent the result of measuring the luminous intensity of scattered light generated after irradiation of excitation light. Meanwhile, the degree of scattering can be defined as the degree to which light emitted from the light emitting devices 211, 212, and 213 is scattered relative to unit mass.

Referring to Figure 3, when the light scattering agent is used at a weight ratio of 1% compared to the encapsulation layer, the scattering degree by Zr oxide (ZrO ₂ ) can be more than twice as large as the scattering degree by Si oxide (SiO ₂ ). there is.

In other words, when comparing the scattering degree of the same content, it can be said that the scattering degree of Zr oxide (ZrO ₂ ) is superior to that of Si oxide (SiO ₂ ). Therefore, when Zr oxide (ZrO ₂ ) is used, the scattering effect can be increased even when a small amount is used.

As the scattering degree of Si oxide (SiO ₂ ) and Zr oxide (ZrO ₂ ) was confirmed, for example, when Zr oxide (ZrO ₂ ) was used at a 1% weight ratio (1 wt%) with a size of 1 ㎛, Si oxide (SiO ₂ ) may be approximately equivalent to the case of using 20% weight ratio (20wt%) with a size of 5 ㎛.

When two or more of these light scattering agents are used together, luminance is improved by reducing the particle size applied within the encapsulation layer.

In addition, when dispersing the light scattering agent in the encapsulation layer, there may be a tendency for it to settle in the direction of the substrate 230 due to its mass. When two or more light scattering agents are used together, the size and shape of these particles may vary. By making changes, you can prevent sedimentation of the light scattering agent.

On the other hand, when two or more light scattering agents are used together, the refractive index can be changed through changes depending on the combination of several types of scattering agents, and the overall content of the scattering agent can be reduced.

Figure 4 is a comparative example, a graph showing the change in luminance according to the viewing angle of the display device in a state in which a light scattering agent is not applied. Additionally, Figure 5 is a graph showing the change in luminance according to viewing angle of the display device according to an embodiment of the present invention.

Referring to Figure 4, it shows the distribution of luminance of white light according to viewing angle. When the light scattering agent as shown is not applied, it can be seen that the luminance distribution is biased toward a positive angle based on 0 degrees.

The light emitting device 210 usually has a compound semiconductor crystal grown on a crystal substrate such as sapphire, and the light emitting device 210 has a chip slope as schematically shown in FIGS. 1 and 2.

The reason why the light emitting device 210 has a chip tilt may be due to the characteristics of the crystal plane during the chip manufacturing process. Typically, the substrate or compound semiconductor crystal forming the light emitting device 210 has a hexagonal lattice inclined crystal plane. Therefore, in the process of cutting the light emitting devices 210 into individual chips after growing them, the individual light emitting devices 210 are cut by these crystal planes and are not cut in a perfectly vertical direction. In other words, the individual light emitting device 210 has a vertical cross-sectional shape of a parallelogram rather than a rectangular parallelepiped.

In addition, the chip inclination of the light emitting device 210 may be due to tilt due to soldering or adhesion of the light emitting device 210. That is, when soldering or adhering the light emitting device 210 to the electrode pad 220, inclination may occur due to non-uniformity of the solder or adhesive.

Accordingly, as shown in FIG. 4, the light emitted from the light emitting device 210 has a beam angle that is not uniform and is biased with respect to the center of the light emitting device 210 chip.

At this time, if the light scattering agent is not applied, the non-uniform light distribution due to the chip inclination may be revealed as is. As a result, a luminance deviation phenomenon in which light emitted from the display panel 200 is biased toward a specific direction may occur. Ultimately, color differences may occur depending on the viewing angle of the display device.

However, as shown in Figure 5, according to one embodiment of the present invention, for example, when two or more light scattering agents are used together, at both positive and negative angles with respect to 0 degrees. It can be seen that it has a uniform luminance distribution.

In this way, for example, in an embodiment in which Zr oxide (ZrO ₂ ) and Si oxide (SiO ₂ ) are distributed in the encapsulation layer, luminance deviation of the display panel 200 can be prevented.

When the encapsulation layers 240 and 253 containing the light scattering agents 250, 251 and 252 having the characteristics described above are located on the display panel 200, non-uniformity due to the chip inclination of the light emitting element 210 A light distribution can be uniformized.

As a result, the luminance deviation phenomenon in which the light emitted from the display panel 200 is biased in a specific direction can be resolved. Ultimately, it is possible to have uniform color without causing color differences depending on the viewing angle of the display device.

In this way, the phenomenon in which colors are perceived differently depending on the position and angle with respect to the display panel 200 (non-uniform reduction in luminance) can be improved.

In addition, as described above, the light scattering agents 250, 251, and 252 are materials with a relatively high refractive index and have the effect of improving the refractive index. Light scattering agents 250, 251, and 252 having such a high refractive index can exert a large scattering effect even when added in a small amount.

In one example, the light scattering agents 250, 251, and 252 may have an amorphous particle shape with a median size of approximately 20 nm to 1 μm. These light scattering agents (250, 251, 252) can be added to the encapsulation layers (240, 253) through a dispensing process. The light scattering agents (250, 251, 252) having the above small size are added to the encapsulation layer (240, 253) through a dispensing process. It can have stability. In addition, it can have the advantage of less sedimentation after going through the curing process after the dispensing process.

As an exemplary embodiment, the light scattering agents 250, 251, and 252 may include Zr oxide (eg, ZrO ₂ ). Since this Zr oxide is a material with a high refractive index (2.3), it can have a relatively large scattering effect.

As described above, Zr oxide has a greater refractive index than silicon oxide (SiO ₂ ), so it can exert a large scattering effect.

Figure 6 is a cross-sectional schematic diagram showing a display device according to a third embodiment of the present invention.

As shown in FIG. 6, the display panel 200 can implement an image by unit pixels 210 (211, 212, 213) arranged on the substrate 230. Encapsulation layers 242, 253, and 260 may be formed on these unit pixels 210; 211, 212, and 213.

Unit pixels 210 (211, 212, 213) may be formed by light emitting elements (211, 212, 213). For example, the unit pixel 210 may include a red light-emitting device 211, a green light-emitting device 212, and a blue light-emitting device 213.

The red light-emitting device 211, green light-emitting device 212, and blue light-emitting device 213 forming the unit pixel 210 may be electrically connected to the electrode pad 220 arranged on the substrate 230.

Meanwhile, unlike shown, the unit pixel 210 may include a stacked light emitting device (LED) with red, green, and blue colors in a single chip structure.

A composite optical film 100 may be positioned on the display panel 200. In this way, the composite optical film 100 can be attached to the display panel 200. The display panel 200 to which the composite optical film 100 is attached may be referred to as a display device 10.

As an exemplary embodiment, the encapsulation layers 242, 253, and 260 include a first layer 242 covering a plurality of light emitting devices 211, 212, and 213, and a second layer located on the first layer 242. It may include (253).

Additionally, the encapsulation layers 242, 253, and 260 may further include a third layer 260 located on the side of the plurality of light emitting devices 211, 212, and 213. This third layer 260 may fill the upper surface of the substrate 230 and the side surfaces of the light emitting devices 211, 212, and 213.

As described above, the first layer 242 and the second layer 253 may include fillers 250 and 252. These fillers 250 and 252 may include a first filler 250 and a second filler 252 having different optical properties. Here, the optical characteristic may be a characteristic of refracting or scattering light emitted from the light emitting device 210.

Additionally, the third layer 260 may include a third filler 261. For example, the third layer 260 may include a third filler 261 having a different scattering degree from the first filler 250 and the second filler 252. That is, the third layer 260 may include a third light scattering agent 261 having a different scattering degree from the first light scattering agent 250 and the second light scattering agent 252.

As an exemplary embodiment, the scattering degree of the third light scattering agent 261 may be higher than that of the first light scattering agent 250 and the second light scattering agent 252.

Additionally, as an example, the height of the third layer 260 may be equal to or smaller than the height of the light emitting device 210. For example, the thickness of the third layer 260 may be 20 nm to 120 ㎛. This may be a thickness range considering the minimum size (10 nm) of the third light scattering agent 261 and the chip thickness of the light emitting device 210, which is 80 to 100 ㎛.

The fillers 250, 252, and 261 may include at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof. For example, the fillers 250, 252, and 261 may be spherical or amorphous. For example, the first filler 250 may be amorphous and the second filler 252 may be spherical. Additionally, the third pillar 261 may be spherical.

Additionally, as described above, for example, the first filler 250 may include Zr oxide. Additionally, as an example, the second filler 252 may include Si oxide. For example, the third light scattering agent 261 may include Ti oxide (TiO ₂ ).

At this time, the optical characteristics of the first pillar 250 may be different from the optical characteristics of the second pillar 252. As mentioned above, the optical characteristic may be a characteristic of refracting or scattering light emitted from the light emitting device 210.

Additionally, the characteristic of refracting or scattering light emitted from the light emitting device 210 can be expressed as a scattering degree. Redundant descriptions of scattering diagrams will be omitted.

As such, according to an embodiment of the present invention, the first filler (250; first light scattering agent), the second filler (252; second light scattering agent), and the third filler (261; third light scattering agent) The color difference of light emitting devices can be improved and the surface haze phenomenon can be improved by using a complex light scattering agent containing the light-emitting device.

The light scattering agents 250, 252, and 261 may interfere with the straight path of light emitted from the light source (light-emitting device) forming the unit pixels 211, 212, and 213, causing light scattering, which is a type of random reflection. Therefore, the light scattering agents 250, 252, and 261 can prevent the luminance deviation phenomenon in which the light emitted from the unit pixels 211, 212, and 213 is biased in a specific direction.

In addition, the light scattering agents 250, 252, and 261 can improve the phenomenon in which colors appear differently depending on the left and right positions and angles relative to the position of the substrate 230 (for example, a phenomenon in which the decrease in luminance is not uniform). You can.

Scattering effect when using a composite light scattering agent including a first filler (250; first light scattering agent), a second filler (252; second light scattering agent), and a third filler (261; third light scattering agent) can be increased, and a high content of filler (light scattering agent) can be added.

Generally, when the same amount is used, the effect of the light scattering agent is in the order of TiO ₂ , ZrO ₂ and SiO ₂ .

In the case of TiO ₂ , the light scattering effect is the best, but it has a strong white turbidity (a cloudy white appearance), so to achieve a light scattering effect that does not affect the blackness of the product, it is recommended to mix it in a very small amount (0.01 wt%). It is advantageous. Therefore, the possibility of errors occurring during weight management and process application may be relatively high.

Therefore, as exemplified above, TiO ₂ with the highest light scattering effect can be used as the third light scattering agent 261 in the third layer 260 for the light scattering effect on the side portion of the chip of the light emitting device 210, ZrO ₂ can be used in the first layer 242, which is the uppermost layer, and SiO ₂ can be used in the second layer 253, which is the uppermost layer.

In this way, the light scattering agent with the lowest degree of light scattering (the second light scattering agent 253) may be located at the top. This may be because higher light scattering can affect the loss of blackness of the display. Therefore, the topmost part of the display can be composed of materials and contents with the lowest light scattering rate.

For other parts not described, the descriptions of the first and second embodiments described above may be equally applied. Therefore, redundant explanations are omitted.

Figure 7 is a cross-sectional schematic diagram showing a display device according to a fourth embodiment of the present invention. Additionally, Figure 8 is an enlarged view of the side optical layer of the display device according to the fourth embodiment of the present invention.

As shown in FIG. 7 , the display panel 200 can implement an image using unit pixels 210 (211, 212, 213) arranged on the substrate 230. Encapsulation layers 241 and 253 may be formed on these unit pixels 210 (211, 212, 213). The configuration of these encapsulation layers 241 and 253 may be the same as that of the second embodiment.

Unit pixels 210 (211, 212, 213) may be formed by light emitting elements (211, 212, 213). For example, the unit pixel 210 may include a red light-emitting device 211, a green light-emitting device 212, and a blue light-emitting device 213.

The red light-emitting device 211, green light-emitting device 212, and blue light-emitting device 213 forming the unit pixel 210 may be electrically connected to the electrode pad 220 arranged on the substrate 230.

Meanwhile, unlike shown, the unit pixel 210 may include a stacked light emitting device (LED) with red, green, and blue colors in a single chip structure.

A composite optical film 100 may be positioned on the display panel 200. In this way, the composite optical film 100 can be attached to the display panel 200. The display panel 200 to which the composite optical film 100 is attached may be referred to as a display device 10.

As an exemplary embodiment, the encapsulation layers 241 and 253 include a first layer 241 covering a plurality of light emitting devices 211, 212, and 213, and a second layer 253 located on the first layer 241. ) may include.

As described above, the first layer 241 and the second layer 253 may include fillers 250 and 252. These fillers 250 and 252 may include a first filler 250 and a second filler 252 having different optical properties. Here, the optical characteristic may be a characteristic of refracting or scattering light emitted from the light emitting device 210.

Additionally, the configuration of the encapsulation layers 241 and 253 and the fillers 250 and 252 may be the same as that of the second embodiment, so duplicate descriptions will be omitted.

Meanwhile, the side optical layer 263 may be located on the side of the encapsulation layers 241 and 253 and the composite optical film 100 located on the substrate 230.

As mentioned above, a modular display device that implements a larger display area by combining a plurality of display devices 10 can be implemented. For example, the display device 10 may be one display module that forms a modular display device. In this way, a plurality of display devices 10 can be combined in parallel to form a modular display device. In this case, the side optical layer 263 may be located on the end side of each module display device 10.

As an exemplary embodiment, the side optical layer 263 is provided with a fourth filler (fourth light scattering agent 265) having a different scattering degree from the first light scattering agent 250 and the second light scattering agent 252; FIG. 8 reference) may be included.

At this time, the scattering degree of the fourth light scattering agent 265 may be lower than the scattering degree of the first light scattering agent 250 and the second light scattering agent 252.

Referring to FIG. 8, the side optical layer 263 may be formed by dispersing the fourth light scattering agent 265 inside the resin layer 264. At this time, the thickness of the side optical layer 263 may be 20 nm to 50 ㎛.

It is advantageous that the light scattering degree of the fourth light scattering agent 265 included in the side optical layer 263 is less than 10% of the light scattering degree of the first light scattering agent 250 and the second light scattering agent 252.

The side optical layer 263 overlaps or multiplies the light emitted from the light emitting element 210 and scattered by the first light scattering agent 250 and the second light scattering agent 252 with the scattered light emitted from the adjacent module display device. You can prevent it from happening.

In some cases, the fourth filler 265 included in the side optical layer 263 may use an absorber rather than a light scattering agent.

For other parts not described, the descriptions of the first to third embodiments may be equally applied.

The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified and implemented in other embodiments by a person with ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be construed as being included in the scope of the present invention.

In addition, although the above description has been made focusing on the examples, this is only an example and does not limit the present invention, and those skilled in the art will understand the above examples without departing from the essential characteristics of the present embodiment. You will be able to see that various modifications and applications are possible. For example, each component specifically shown in the examples can be modified and implemented. And these variations and differences in application should be construed as being included in the scope of the present invention as defined in the appended claims.

According to the present invention, it is possible to provide a display device that can improve light uniformity by including a composite filler.

Claims (20)

1. wiring board;

   electrode pads defined on the wiring board;

   a plurality of light emitting elements connected to the electrode pads to form unit pixels;

   an encapsulation layer formed on the wiring board to cover the plurality of light emitting devices;

   An optical film positioned on the encapsulation layer; and

   Comprising a light scattering agent dispersed and distributed within the encapsulation layer,

   The light scattering agent is,

   a first light scattering agent; and

   A display device comprising a second light scattering agent having a different scattering degree from the first light scattering agent.
2. The display device of claim 1, wherein the light scattering agent includes at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof.
3. The method of claim 1, wherein the encapsulation layer is:

   a first layer covering the plurality of light emitting devices; and

   A display device comprising a second layer located on the first layer.
4. The display device of claim 3, wherein the second light scattering agent is included in the second layer.
5. The display device according to claim 3, wherein the scattering degree of the first light scattering agent is greater than the scattering degree of the second light scattering agent.
6. The display device of claim 1, wherein the encapsulation layer further includes a third layer located on sides of the plurality of light emitting devices.
7. The display device according to claim 6, wherein the third layer includes a third light scattering agent having a different scattering degree from the first light scattering agent and the second light scattering agent.
8. The display device according to claim 7, wherein a scattering degree of the third light scattering agent is higher than a scattering degree of the first light scattering agent and the second light scattering agent.
9. The display device according to claim 6, wherein the height of the third layer is equal to or smaller than the height of the light emitting element.
10. The display device according to claim 1, further comprising a side optical layer located on a side of the encapsulation layer.
11. The display device of claim 10, wherein the side optical layer includes a fourth light scattering agent having a different scattering degree from the first light scattering agent and the second light scattering agent.
12. The display device according to claim 1, wherein the diameter or size of the light scattering agent is 10 nm to 10 ㎛.
13. wiring board;

    electrode pads defined on the wiring board;

    a plurality of light emitting elements connected to the electrode pads to form unit pixels;

    an encapsulation layer formed on the wiring board to cover the plurality of light emitting devices;

    An optical film positioned on the encapsulation layer; and

    It includes a filler dispersed and distributed within the encapsulation layer,

    The filler is,

    A first filler containing Zr oxide; and

    A display device comprising a second filler containing Si oxide.
14. The method of claim 13, wherein the encapsulation layer is:

    a first layer covering the plurality of light emitting devices; and

    A display device comprising a second layer located on the first layer.
15. The display device of claim 14, wherein the second pillar is included in the second layer.
16. The display device of claim 13, wherein the encapsulation layer further includes a third layer located on sides of the plurality of light emitting devices.
17. The display device of claim 16, wherein the third layer includes a third filler having different optical properties from the first filler and the second filler.
18. The display device of claim 17, wherein the third filler includes Ti oxide.
19. The display device of claim 17, wherein the degree of light scattering of the third filler is higher than that of the first filler and the second filler.
20. According to clause 13,

    It further includes a side optical layer located on a side of the encapsulation layer,

    A display device, wherein the side optical layer includes a fourth scattering agent having a different scattering degree from the first light scattering agent and the second light scattering agent.

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